1. Field of the Invention
The present invention relates to a steering system having a tilt mechanism and a pop up mechanism both for controlling tilting of a steering wheel, with some parts shared by the tilt mechanism and the pop up mechanism. Moreover, the steering system under the present invention includes a telescope mechanism for moving the steering wheel substantially in a forward-backward direction.
2. Description of the Related Art
For improving seat occupant's comfort (namely, getting in and getting off the vehicle with ease), various types of steering systems are proposed, including one that has a steering wheel capable of popping up to a certain position when the seat occupant gets off the vehicle and moving back to a driving position after the seat occupant gets in the vehicle.
Recently, another steering wheel having a greater popping up angle for further improving the seat occupant's comfort is in practical use, as is disclosed in Japanese Patent Unexamined Publication No. 2000-71798 (=JP2000071798).
A steering system according to Japanese Patent Unexamined Publication No. 2000-71798 (=JP2000071798) is mounted to a vehicle having an automatic transmission. When the vehicle is in an idle state or an ignition key is turned on, the steering wheel is allowed to pop up to an angle over an ordinary driving angle. The steering wheel includes a steering position selecting means, a steering position sensing means, a shift lever parking position sensing means, a foot brake pedal position sensing means, a steering moving means, a shift lever locking means, and a steering movement controlling means. The shift lever locking means locks (disables) shift selection. The steering movement controlling means controls the shift lever locking means and the steering movement controlling means by taking in a signal of each of the steering position selecting means, the steering position sensing means, the shift lever parking position sensing means and the foot brake pedal position sensing means.
The steering movement controlling means makes the following control:                With the steering wheel popped up, the seat occupant even stepping on a foot brake pedal cannot make a shift selection due to the shift lever locking means. Moreover, the seat occupant even stepping on the foot brake pedal cannot unlock the shift lever locking means unless the steering wheel is returned to a driving position completely.        On the other hand, the steering wheel returned to the driving position completely may allow the seat occupant to unlock the shift lever locking means by stepping on the foot brake pedal.        
Summarizing the above, the seat occupant can unlock the shift lever locking means by stepping on the foot brake pedal only in a state of the steering wheel completely returned to the driving position. With the steering wheel in an inoperable position, the seat occupant stepping down the foot brake pedal cannot make the shift selection from parking to other speed range, even when the vehicle is in the idle state or the ignition key is turned on.
With the steering system according to Japanese Patent Unexamined Publication No. 2000-71798 (=JP2000071798), however, a pop up mechanism popping up the steering wheel greatly upward in the vehicle's stop and the like may cause an interference to a steering column's cover with an instrument panel which is disposed in front of the seat occupant in the vehicle.